Rotor blades in turbomachinery occasionally suffer minor Foreign Object Damage (FOD). This need not necessitate the replacement of the whole component, but the aerodynamic surface of the blade must be restored to ensure optimum operation of the blade. This causes a problem where the rotor blade is fixed in position inside an engine assembly. While the engine can be stripped down to allow for the temporary removal of the blade while it is machined, it is often preferable to machine the blade “in-situ” to avoid lengthy engine down time. Such machining can be achieved easily manually if the blade can be reached from an engine inlet or exit. If the blade is inaccessible then conventional blending by hand may not be possible. Under these circumstances a device can be inserted through a boroscope hole with a small powered grinding wheel at its end. This enables grinding and blending of notches to be carried out remotely. The process can prove difficult because of the nature of blade mounting, which, at rest, tends to leave the blade loosely mounted. Hence as the blade is ground it may begin to chatter through lack of support or damping. Alternatively, because of the size or geometry of the blade, it may be relatively flexible, and so the blade may flex away from the blending tool as pressure is applied during the machining process. The effectiveness of the grinding operation is therefore reduced.